Radiation grill

ABSTRACT

A radiation grill unit (1) comprises (i) a food support unit (100) with bars (110), (ii) a radiation unit (200) that includes a reflector (210) (with reflector opening (223)) hosting an IR radiation heater (220), wherein the radiation unit (200) is configured to provide IR radiation (201) in a direction of the food support unit (100), and (iii) a radiation grill unit cavity (3) configured to host a drip tray (300). The drip tray is configured in the radiation grill unit cavity below a lower part edge of the reflector and out of a line of sight of direct IR radiation from the IR radiation heater. The drip tray further comprises a drip tray face and at least one drip tray reservoir configured at a side edge of the drip tray in a location that does not receive direct IR radiation, and configured to store a lipid comprising liquid.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of granted U.S. patentapplication Ser. No. 15/024,576, filed on Mar. 24, 2016, which is theU.S. National Phase application under 35 U.S.C. § 371 of InternationalApplication No. PCT/EP2014/069419, filed on Sep. 11, 2014, which claimsthe benefit of European Application 13185697.3 filed on Sep. 24, 2013.These applications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The invention relates amongst others to a radiation grill and to amethod for cooking a food product with such radiation grill.

BACKGROUND OF THE INVENTION

Electrical radiation grills are known in the art. EP1444939, forinstance, describes a cooking apparatus capable of effectively utilizingthermal energy of a heating unit to heat food including a cabinet openedat a top surface thereof to provide an opening over which food to becooked is laid. A grill unit is seated in the opening of the cabinet soas to support the food over the opening. A heating unit is provided inthe cabinet so that a front surface thereof faces the grill unit toradiate thermal energy to the grill unit. A plurality of reflectingmembers are provided at predetermined positions around a rear surface ofthe heating unit and are installed to be spaced apart from each other bya predetermined gap to provide an air layer between the reflectingmembers. The construction of the cooking apparatus allows far infraredrays radiated from a rear surface of the heating unit to be reflected toa front of the heating unit, in addition to preventing heat from beingtransmitted from the heating unit to a rear portion of the heating unitdue to an air layer provided between the reflecting members. Accordingto EP1444939, most of the thermal energy generated from the heating unitmay be used for cooking the food.

FR291204.8 describes a cooking appliance of the gas grill type. Theappliance comprises two radiant gas burners with radiating surfaces bywhich IR radiation is radiated to a cooking grid but also to a cookingtray mounted in a frame below the radiant burners.

SUMMARY OF THE INVENTION

Disadvantages of prior art systems may include the fact that foodproducts can easily burn. Further disadvantages may include inefficientuse of electric energy. Prior art systems may also suffer from theproblem that fat and oil drip in a drip tray, which may lead to dirtytrays when the fat or oil turns into carbonized products. Systems thatinclude drip trays with water may lead to difficult handling by theuser. Prior art systems may also lead to undesired smoke creation,because of this carbonization of oil.

Hence, it is an aspect of the invention to provide an alternativeradiation grill unit (herein also indicated as “grill” or “smokelessgrill” or “apparatus”), which preferably further at least partlyobviates one or more of above-described drawbacks.

The invention especially deals with radiation grills, which use infraredheaters in combination with reflectors to direct the heat to the food.The grill has a food support unit, such as a grill grid, which has thefunction to hold e.g. meat (or vegetables, fish, etc.) in or close tothe area where the radiation is pointed at.

The present invention is especially directed to a radiation grill unitcomprising (i) a food support unit, such as a grill grid (herein alsoindicated as “grid”), and (ii) a(n electrical) radiation unit, theradiation unit especially comprising a reflector hosting an (electrical)IR radiation heater, wherein the radiation unit is configured to provideIR radiation in a direction of the food support unit. Optionally, theradiation grill unit further comprises (iii) a radiation grill unitcavity configured to host a drip tray (herein also indicated as “tray”).

In an embodiment, the food support unit comprises a grill grid withbars, the grill grid comprising a food support side and a radiationside. In yet another embodiment, the food support unit comprises one ormore (elements) selected from the group (consisting) of a spit, askewer, a clamp, and a hook. In this invention especially the grill gridwill be described, because some surprisingly advantageous parameters arespecially designed for this grill unit.

Hence, in a further embodiment, the food support unit may be integralpart of the radiation grill unit, such as in the case of a spit. In yetanother embodiment, the radiation grill unit is configured to supportthe food support unit, such as in the case of a grill grid. In anembodiment, wherein the food support unit is a unit that is notintegrated with or temporarily part of the grill unit, the food supportunit may be rotatable within the radiation grill unit, such as in caseof a spit. In yet another embodiment, the food support unit is a unitthat is not integrated with or temporarily part of the grill unit.Hence, in a further aspect, the invention also provides an arrangementof a radiation grill unit and a food support unit, as well as a methodof cooking a food product with such arrangement.

Herein, the term “food product” may e.g. refer to (a piece of) meat, (apiece of) fish, (a piece of) fruit, (a piece of) vegetable etc. Further,the term “food product” may also relate to a plurality of food products.

Since burning fat (or other food waste material) creates smoke, it isdesired to prevent that the drip tray, which collects the fat that dripsfrom the food, gets hot via direct or indirect radiation. The reflectorcan be constructed in such a way that it minimizes the amount of directradiation from the heater that reaches the drip tray (see elsewhere).However, there is also indirect radiation from parts in the system thatheat up (e.g. the glass plates; see elsewhere). For this reason, thedrip tray may still gradually heat up, no matter how well the reflectoris designed. The drip tray can be made from a highly reflectivematerial, to minimize the amount of radiation that gets transformed intoheat, but handling and cleaning the drip tray will cause thisreflectivity to reduce over time. Moreover, the fat itself, which formsa layer on the bottom of the drip tray, absorbs radiant energy, causingit to heat up as well.

Herein, the invention provides a specially designed drip tray that maybe configured to drain away the fat to minimize the risk that the fat inthe drip tray overheats and causes smoke.

Especially, the surface on which the fat falls (drip tray face) may havea sloped surface, so that the fat starts to flow to the edge where thesurface is at its lowest points. Good results seem to be obtained when areservoir for collecting said fat and/or oil is positioned on the sidesof the grill, particularly on the two short sides, which can beprotected from radiation.

After prolonged grilling of fat-rich food, such as hamburgers, a lot offat can collect on these edges, so that the fat level will rise andspread over the whole surface again.

Hence, in an aspect, the invention provides a radiation grill unitcomprising (i) a food support unit, and (ii) a radiation unit,especially comprising a reflector hosting an electrical IR radiationheater, wherein the radiation unit is configured to provide IR radiationin a direction of the food support unit, wherein the radiation grillunit comprises said drip tray, wherein the drip tray is especiallyconfigured in the radiation grill unit cavity out of the line of sightof direct IR radiation from the radiation heater, wherein the drip traycomprises a drip tray face and a drip tray reservoir (herein alsoindicated as “reservoir”) configured at an edge of the drip tray andconfigured to (temporarily) store a lipid comprising liquid, and whereinthe drip tray face comprises collection means configured to guide thelipid comprising fluid from the drip tray face to the drip trayreservoir. Even more especially, the invention provides a radiationgrill unit comprising (i) a grill grid with bars, the grill gridcomprising a food support side and a radiation side, (ii) a radiationunit, especially comprising a reflector hosting an (electrical) IRradiation heater, wherein the radiation unit is configured to provide IRradiation in a direction of the radiation side of the grill grid, and(iii) a radiation grill unit cavity configured to host a drip tray,wherein the radiation grill unit comprises said drip tray, wherein thedrip tray is especially configured in the radiation grill unit cavityout of the line of sight of direct IR radiation from the radiationheater, wherein the drip tray comprises a drip tray face and a drip trayreservoir configured at an edge of the drip tray and configured to(temporarily) store a lipid comprising liquid, and wherein the drip trayface comprises collection means configured to guide the lipid comprisingfluid from the drip tray face to the drip tray reservoir.

With such drip tray, lipid droplets are collected at the drip tray face,with migrate then to the drip tray reservoir. This migration or drainageis especially facilitated by the collection means. For instance, thedrip tray face may have a V-shape or a Λ-shape, especially a V-shape.Further, the drip tray face may include a curvature, to facilitatemigration of liquid lipid (and other material) to the reservoir. Thereare a number of reasons to choose a configuration that facilitatesdrainage of the fat and other liquids to the middle (and to thereservoir(s) of the drip tray, especially at the edge(s) of the driptray). Amongst others, the hottest spots in the drip tray may be theareas near to the radiation unit (especially due to the indirectradiation). In the drip tray these spots are the highest to let thefat/liquid flow away from that area to a location that does not evenhave indirect radiation as the reservoirs may be behind and/or belowcavity edges of the device. Further, tests have shown that a layer ofoil/fat may absorb much more radiation and turning it into heat energy.If the fat flows away after falling in the drip tray the layer will notstay there or otherwise be very thin. Less radiation will be transferredinto heat energy. Further, when droplets fall into a level of liquidthere is a chance of splashing to the very hot reflector (glass) andthat creates immediately smoke and noise. The drip tray may be the mostshallow near to the hot reflector (glass).

Note that especially herein the drip tray does not receive direct IRradiation from the radiation unit(s). It appeared that this should beprevented in view of efficiency, smoke production, and in view ofcleaning aspects. For users the effects are also beneficial, as cleaningmay take less time and life time of the grill unit may be increased. Asthe drip tray may stay relatively cool, there may be substantially nosmoke production.

In a specific embodiment, the drip tray face may comprise a centralcollection channel in fluid connection with the drip tray reservoir. Asindicated above, especially the drip tray reservoir has a storage volumefor the lipid comprising liquid (or any other liquid) in the range ofabout 50-350 ml, such as 100-250 ml, like at least 150 ml. As indicatedabove, the term “drip tray reservoir” may refer to a plurality ofreservoirs (having in total such storage volume). In yet a furtherembodiment, see also above, the drip tray face comprises a curvatureconfigured to guide the lipid comprising fluid from the drip tray faceto the drip tray reservoir. In a further specific embodiment, the driptray face has a saddle-like shape, and wherein the drip tray comprisestwo or more drip tray reservoirs at the edges of the drip tray.

The drip tray may for instance be made via a process such as injectionmolding (of e.g. heat resistant plastic) or deep drawing of metal(stainless) steel or aluminum, with possibly a dish washer resistant andeasy to clean surface like a chromized (provided with a chromium layer)or enameled surface. Further, the drip tray may (thus) essentiallyconsist of a material like steel, aluminum, or optionally heat resistantplastic, especially stainless steel or aluminum.

As indicated above, the drip tray may be configured to store a lipidcomprising liquid. As will be clear to a person skilled in the art, thismay be a temporary storage, as e.g. after use the drip tray may becleaned. Further, the phrase “configured to store a lipid comprisingliquid” may especially indicate that the drip tray is able to hold orstore a liquid (and/or solid or solidified) material. This should notnecessarily (only) include a lipid comprising liquid.

Especially, a radiation grill unit as defined herein is provided,wherein all direct IR radiation that escapes from the radiation unit isreceived by the radiation side of food support unit, especially thegrill grid.

Common (electrical) grills use a hot grid or hot plate to grill thefood. The temperature of such grids or plates can easily reachtemperatures in the range of 200-250° C. The disadvantage of this isthat the food can easily burn, which is unhealthy, and that fat drippingfrom the food will burn and create smoke, which is undesired especiallywhen grilling indoors.

With the radiation grill as suggested herein it is aimed to transferenergy from the heater to the meat or other type of food with thehighest efficiency. Another goal is to prevent the drip tray gets hotvia direct or indirect radiation heat. This is important to preventsmoke creation: fats and oils collected in the drip tray may not get toohot to prevent boiling and smoking. The present invention providesamongst others a grilling grid design that may prevent smoke creation,may create an optimal efficiency, and may make the grill easier toclean.

Herein, the term “grill grid”, or “grilling grid” or “grid” especiallyrefers to a 1D array of bars. Bars may also be indicated as “rods”.These bars may especially be arranged parallel. The bars may essentiallyhave a round or oval cross-section of a substantial part, such as atleast 90%, of their length.

Some specific elements in this invention that can be used alone or canbe combined to get the best effect may include (a) relative thin gridbars, relative large distances or areas in-between the grid bars, (b) anoil and fat guidance, and (c) an optimal grid bar direction. Inembodiments of the present invention the grid is especially executed ina way that it reflects the radiation energy as little as possible andthat it blocks the radiation energy as little as possible. It may alsoespecially guide oil and fat drops to a location where it is easy toclean when dropping down.

Hence, in an aspect the invention provides a radiation grill unitcomprising (i) a food support unit, and (ii) a radiation unit,especially comprising a reflector hosting an electrical IR radiationheater, wherein the radiation unit is configured to provide IR radiationin a direction of the food support unit, especially in the direction ofa grill grid, wherein the food support unit comprises said grill gridwith bars, wherein especially the bars have bar diameters (DB) and bardistances (PB), wherein the bar diameters (DB) are selected from therange of 1-4 mm, and wherein especially a ratio PB/DB between the bardistances (PB) and bar diameters (DB) is selected from the range of2-10, such as 2-8. Herein, the “grid” especially refers to a 1D array ofbars, and not to a 2D array of bars, with e.g. two sets of bars whichare perpendicularly arranged to each other.

Especially, the invention provides a radiation grill unit comprising (i)a grill grid with bars (herein also indicated as “grid bars”), the grillgrid comprising a food support side and a radiation side, (ii) aradiation unit, especially comprising a reflector hosting an(electrical) IR (infrared) radiation heater, wherein the radiation unitis configured to provide IR radiation in a direction of the radiationside of the grill grid, and (iii) a radiation grill unit cavityconfigured to host a drip tray, wherein especially the bars have bardiameters (DB) and bar distances (PB), wherein the bar diameters (DB)are selected from the range of 1-4 mm, and wherein especially a ratioPB/DB between the bar distances (PB) and bar diameters (DB) is selectedfrom the range of 2-10, such as 2-8. The distances between the bars areherein distances between the centers of the bars. Hence the distancebetween the bars can also be indicated as pitch. Further, in general thepitch is uniform over the grill grid and also the bar diameter isuniform over the grill grid.

It appears that with such conditions, well cooked food products may beobtained in an efficient way, whereas with other conditions theefficiency and or the quality of the food product may be worse. Lowerefficiencies increase the change on smoking and other undesired aspects.Such configuration, as especially indicated above, may allow a moreefficient use of energy and may prevent unnecessary heating of the wholesystem. In a specific embodiment, the bar diameters (DB) are selectedfrom the range of 2-3 mm, and the ratio (PB/DB) between the bardistances (PB) and bar diameters (DB) is selected from the range of 5-8,such as 5.5-7.5. This may even lead to better results.

The radiation side of the grill grid is the side of the grid directed tothe radiation unit(s); the food support side is the opposite side of thegrill grid; i.e. the part on which the food product(s) are arrangedduring use of the grill unit.

It further appears that to minimize the area that will not be reached bythe infrared light because of the grid (shadow) the grid bars directionmay especially chosen to be the same direction as the light (beams) andnot perpendicular. Hence, in a further specific embodiment, the IRradiation heater is elongated (especially an elongated bar) with an axisof elongation wherein the bars are configured in a plane parallel to theIR radiation heater and (wherein the bars are configured) perpendicularto the axis of elongation. In this way, a substantial part of the IRradiation may be parallel to the bars.

Hence, the IR radiation heater is especially elongated, such as having alength of at least 8 cm, such as at least 20 cm, like a length selectedfrom the range of 8-150 cm, like 15-80 cm, such as especially ˜15-50 cm,such as 15-45 cm, such as 30-40 cm. Elongated IR radiation heaters areherein also indicated as linear heaters. Optionally, a radiation unitmay comprise a plurality of IR radiation heaters, which may be arrangedin an embodiment parallel, and which may in another embodiment bearranged in series.

The IR radiation heater is herein especially an electrical radiationheater. For instance, this may be electrically conductive bar, or a(electrically non-conductive) bar with an electrically conductive wirewound around the bar. The IR radiation heater may thus especially have adiameter, which may be in the range of e.g. 2-30 mm, such as 3-20 mm(including optional wiring). By applying a current through theelectrically conductive bar or electrically conductive wire, theelectrically conductive part is heated and generates IR radiation (andoptionally (some) visible radiation).

In a specific embodiment, especially a design for the (electrical) (IR)radiation heater comprises a heater wire wrapped around an electricalinsulated coil. An embodiment is amongst others described in EPapplication number 13162278.9, filed 4 Apr. 2013, which is incorporatedherein by reference. Hence, in a further aspect the radiation heatercomprises a heating tube, comprising a tube, a first resistance wireassociated with the tube, and a second resistance wire associated withthe tube, wherein both the first resistance wire and the secondresistance wire have electrical connections arranged at their ends, forelectrically connecting the resistance wire in an electrical circuit,and wherein at least one of the electrical connections of the firstresistance wire and at least one of the electrical connections of thesecond resistance wire, respectively, are separate from each other. Inan embodiment, at least one of the first resistance wire and the secondresistance wire is arranged inside the tube. In yet a furtherembodiment, the first resistance wire is an outer resistance wirearranged at an outer surface of the tube, and wherein the secondresistance wire is an inner resistance wire arranged inside the tube.Especially, the first resistance wire and the second resistance wirehave different electrical resistance. In an embodiment, the firstresistance wire and the second resistance wire are arranged in series.Optionally, a power connection means may be applied, which powerconnection means may be adapted to be connected to an electrical powersource, and a switching means arranged between the power connectionmeans and the heating tube, wherein the switching means is adapted toassume one of a position for disconnecting the heating tube from thepower connection means, a position for connecting both resistance wiresof the heating tube to the power connection means, and a position forconnecting only one of the resistance wires of the heating tube to thepower connection means.

Hence, the radiation unit may further include an infrastructure forproviding a current to such electrically conductive part of theradiation unit, like electrically conductive wires and a plug. The powersupplied to the IR radiation heater may especially be in the range of500-3000 Watt, such as at least 1000 Watt and/or at maximum 2500 Watt.The power per area supplied to the radiation side of the grill grid(radiation side) may be in the range of 1-2.5 W/cm², especially in therange of 1.5-2.2 W/cm². Below these values, the grilling performance maybecome unacceptable (low), whereas above these values too much smokeproduction may be experienced, and the food may thus burn more easily.

When e.g. meat is grilled, fat and oils will drain out of the meat anddrop down in the direction of the drip tray. For cleanability and smokeprevention it is not preferred that oil drops down on e.g. the radiationunit, such as on a protective window in front of the radiation unit,like glass (see also below). This can be achieved by executing thegrilling grid in a way that at least a part of the (total number of) oildroplets are guided via a sloped underside of the grid (and viagravity), such as for instance away from the glass area (of a protectivewindow, see below). Oil will drop directly in the drip tray and not onthe glass. Herein, oil and fat is also indicated as lipid. Further, theterm “lipid droplet” is used. This term refers to any droplet that maydrip from the food product or grid during use of the radiation grillunit and which contains fat and/or oil. Further substances, like otherfood components, or like carbon, may also be contained in such lipiddroplet. This principle may also apply when cooking fruit and/orvegetables etc. with the (present) radiation grill. Especially then,droplets of water and other material may be formed, such as sugar,carbohydrates, etc. etc. It is also less desired that such droplets leadto undesired sedimentation of (waste) material and (thus) potentialsmoke formation and consequences like cleaning difficulties. Herein, theinvention is especially further described with respect to lipid dropletsby way of example only. However, this term “lipid droplets” and the term“lipid waste” (see below) may be replaced by droplet with food materialor droplet with (food) waste material, respectively.

Hence, in yet a further embodiment, the bars have bar lengths (LB),wherein the bars comprise sloping parts configured to facilitatedripping of a lipid droplet (7), especially into the drip tray, whereinthe sloping parts are especially configured at one or more of a positionwithin 0-10% (of the bar length (LB)) and a position within 90-100% ofthe bar length (LB). The bars have bar ends, and close to those bar endssuch sloping parts may be available, such as for instance within 5 cm,especially within 2 cm of the bar ends. The sloping parts may includefeatures that facilitate dripping of a lipid droplet. When choosing theproper dimensions of the drip tray, the bars and the sloping parts,droplet escaping from the bars may escape above the drip tray. Hence,the sloping parts may especially be configured to facilitate dropletcollection in the drip tray (and not next to the tray, such as on thereflector(s)). Hence, in a specific embodiment, the sloping part(s) maybe configured to facilitate transport of liquid in a direction of themiddle of the bar (i.e. about to a place at the bar at about half of thelength of the bar). Or, in other words, the sloping part(s) may beconfigured to facilitate transport of liquid in a direction away from anend (to which the liquid is closest). Especially, the sloping part(s)may be configured to facilitate transport of liquid in a direction of 5LB (i.e. the middle of the bar), wherein LB is the length of the bar(s).

In general, the bars will have a part that can be used to arrange thefood product on. This may include the entire length of the bar, or asubstantial part thereof. This part is herein also indicated as barsupport part, as it can be used as support for the food product, orintermediate part (see below). Especially, the bars may comprise bar endparts and bar support parts, the bar support part having a length of atleast 80%, especially at least 90%, of the bar length (LB), with thesloping parts between the bar end parts and the bar support part. Thesloping parts will in general be at the radiation side of the grillgrid. Embodiments of the sloping parts may be chosen that have also ageometrical effect on the food support side of the grill grid. Forinstance, the sloping parts may include a curvature in the bars. Hence,for instance a grid may be provided wherein the bars compriseintermediate parts which are arranged lower relative to the bar endparts. Between the bar end parts and the intermediate bar of a bar, acurved bar part may be available. Such curvature in the bar may also beadvantageous to guide the food product to the (desired) (food supportside of the) intermediate part. Here, the curvature especially relatesto a curvature relative to a length axis of the bar(s).

As indicated above, the dimensions and geometry (of the grill bars) maybe chosen to facilitate dripping of lipid droplets in a tray arrangedbelow the grill grid (during use). It may especially be helpful when thesloping parts facilitate the lipid droplets falling in the drip tray dueto gravity. Hence, in yet a further embodiment, the bars compriseintermediate parts between the sloping parts, wherein the intermediateparts have lengths (SPL) in the range of 70-98% of the bar length (LB),wherein the radiation grill unit hosts said drip tray, wherein said driptray has a drip tray width (WT), and wherein the drip tray width (WT) isequal to or larger than the length (SPL) of the intermediate parts. Thefood product may be arranged on the intermediate part (at the foodsupport side (thereof)). In other words, the drip tray width is chosensuch that the drip tray can be arranged under grill grid with thesloping parts over the drip tray. As indicated above, the intermediateparts may be arranged lower relative to the bar end parts (i.e. when thegrill grid is arranged in the grill unit).

The term “radiation unit” may also refer to a plurality of radiationunits. Hence, the grill unit may comprise a plurality of radiationunits. In general, the grill unit comprises two radiation units, or aplurality of sets of two radiation units, which sets of radiation unitsopposite of each other, with the cavity (optionally including the driptray), or (at least) a substantial part thereof, in between. Hence, theinvention further provides an embodiment wherein the radiation grillunit comprises (at least) two radiation units opposite of each other and(configured at both grill edges and) both configured to provide IRradiation in a direction of the radiation side of the food support unit,especially a grill grid, wherein the (at least) two radiation units areconfigured at a smallest radiation unit distance (WRU) from each other,wherein especially the smallest radiation unit distance (WRU) is equalto or larger than the length (SPL) of the intermediate parts. This maysubstantially reduce dripping of lipid droplets (from the food productand/or grill grid) on the radiation unit. However, especially when aprotective window is applied (see below), optionally the smallestradiation distance may be smaller than the length (SPL) of theintermediate parts, as droplets reaching the protective window mayfurther migrate downwards and fall in the drip tray (when the width ofthe drip tray is especially larger than the smallest radiation unitdistance; see also below (when e.g. a protective window lower edge isconfigured above the drip tray face)). In specific embodiments,WT>WRU>SPL. As indicated above, the radiation unit especially comprisesan electrical radiation unit.

In most of the prior art documents the shape of the reflector is notdescribed at all, or at least not in detail. In some prior art systemsthe shape is clearly shown as parabolic. However, a certain portion ofthe energy in such systems appear not (directly) to go to the foodproduct. Some radiation in prior art systems typically also goes to thedrip tray, located at the bottom, heating up the drip tray which appearsto enhance the generation of smoke (during use of the grill).

However, herein a reflector shape is described which maximizes theamount of radiation reaching the food and minimizes the amount of heatgoing to the opposite reflectors, glass shields, housing, drip tray,etc.

Especially, the new reflector shape has been constructed such that oneor more may apply (a) the energy may equally be distributed over thegrilling surface (please note (in this embodiment and other embodiments)that the grill may especially use two reflectors (i.e. especiallyradiation units), so the radiation at a certain point at the foodsupport unit, especially on the grill grid, is the sum of the radiationfrom both sides), and (b) no radiation may reach the opposite reflectorand/or glass shield (i.e. the opposite radiation unit and its optionalprotective window, see also below), nor the drip tray. Hence, in orderto achieve this, the reflector may especially have two main surfaces:(i) a substantially parabolic-shaped surface behind the heater, toachieve a homogenous distribution and (ii) a substantially straightsurface, positioned under an angle, to block the rays that wouldotherwise be directed towards (the drip tray and/or) the oppositereflector, and/or at the same time to improve the homogeneity at thegrid near the edges.

Hence, in an aspect, the invention provides a radiation grill unitcomprising (i) a food support unit, and (ii) a radiation unit,especially comprising a reflector hosting an (electrical) IR radiationheater, wherein the radiation unit is configured to provide IR radiationin a direction of the food support unit, especially comprising (atleast) two radiation units opposite of each other and (especiallyconfigured at both grill edges and) both configured to provide IRradiation in a direction of the food support unit, especially in thedirection of the radiation side of the grill grid, and wherein the (atleast) two radiation units are configured to direct substantially all IRradiation that leaves the respective radiation units to the food supportunit. Even more especially, the invention provides a radiation grillunit comprising (i) a food support unit, especially a grill grid withbars, the grill grid comprising a food support side and a radiationside, (ii) a radiation unit, especially comprising a reflector hostingan (electrical) IR radiation heater, wherein the radiation unit isconfigured to provide IR radiation in a direction of the food supportunit, especially in the direction of the radiation side of the grillgrid, and (iii) a radiation grill unit cavity configured to host a driptray, especially comprising (at least) two radiation units opposite ofeach other and (especially configured at both grill edges and) bothconfigured to provide IR radiation in a direction of the food supportunit, especially in the direction of the radiation side of the grillgrid, and wherein the (at least) two radiation units are configured todirect substantially all IR radiation that leaves the respectiveradiation units to the food support unit. With such configuration,substantially all IR radiation may be directed to the food support unitand substantially no IR radiation, or at least substantially no directIR radiation may impinge on other parts of the grill unit, such as anopposite radiation unit. Further, such configuration may add to an evendistribution of the IR radiation over the radiation side of the foodsupport unit. This may improve efficiency of the grill unit, even thoughprior art seems to teach other configurations, such as projection of asubstantial part of the IR radiation on a wedge shaped drip tray. Suchwedge-shaped drip tray is intended to reflect the heat, and is therebypart of the total reflector system. A disadvantage of such solution maybe that this may cause a very hot drip tray, and thus smoke generation.Further, efficiency of the radiation units may be improved and life timeof the grill unit may also be improved. Herein, the phrase “opposite ofeach other” may especially indicate that the (at least) two radiationunits are each arranged at an end of the grill unit cavity, especiallywith a substantial part of the (remaining) grill unit cavity in between.When the drip tray is arranged in the grill unit cavity, the phrase“opposite of each other” may especially indicate that the two radiationunits are arranged each at a side of the drip tray, with the drip trayin between. Assuming the presence of a grill grid having a width WG, theshortest distance between the two oppositely arranged radiation unitsmay e.g. be in the range of 0.6-1.4 WG, especially 0.8-1.2 WG. Forinstance, the (at least) two radiation units may be configured at bothgrill edges.

In a specific embodiment the (at least) two radiation units areconfigured to direct at least 50% especially at least 70%, such as evenmore especially at least 75% of the total power (W) of the IR radiationthat leaves the respective radiation units to the food support unit,especially the grill grid. The IR radiation that is able to escape fromthe reflector, which may include direct and indirect radiation, may bemeasured with an IR detector, such as a (heat) flux IR radio meter,which are known in the art. By evaluating the signal of the IR detectorat different position, one may evaluate what part of the power reachesthe food support unit, especially the grill grid, and what part of thepower is received by other parts of the grill unit. Note that phraseslike “directing to the grill grid” or “reaching the grill grid” andsimilar phrases may in fact refer to the total cross-sectional area (ofa plane through) the grill grid or the total cross-sectional area of theradiation side of the grill grid.

In yet a further embodiment, the radiation units comprise a lowerreflector part with a lower reflector part edge and an upper reflectorpart with an upper reflector part edge, wherein the (at least) two IRradiation heaters are configured at a first depth (b) below the lowerreflector part edges and at a second depth (d) below the an upperreflector part edges, wherein the radiation heaters are furtherconfigured at a first horizontal distance (a) from the lower reflectorpart edge and at a second horizontal distance (e) from the upperreflector part, wherein the (at least) two radiation heaters areconfigured at a mutual distance (c) from each other, wherein0.6≤a*d/(b*(c−e))≤1.4. Especially, 0.8≤a*d/(b*(c−e))≤1.2. It appearsthat with especially these dimensions very efficient the food productmay be irradiation whereas dimensions outside these ranges may be lessefficient. As indicated above, sets of two (oppositely arranged)radiation units may be applied.

In yet a further embodiment, the radiation heater of a first radiationunit is configured below a line through the upper reflector part edge ofthe radiation heater of a second radiation unit and the lower reflectorpart edge of the first radiation unit. Especially, a central axis oraxis of elongation of the radiation heater of a first radiation unit isconfigured below a line through the upper reflector part edge of theradiation heater of a second radiation unit and the lower reflector partedge of the first radiation unit. Hence, with such dimensions, direct IRradiation of the opposite radiation unit may substantially be prevented.

As indicated above, especially the radiation unit(s) comprise a lowerreflector part comprising faces with mutual angles (α), and an upperreflector part having a parabolic-like shape. Especially, this lowerreflector part may comprise two faces, having a mutual angle (α) (seeFIG. 3b ) in the range of 45-135°, especially 75-105°. Hence, thereflector(s) may essentially comprise of three faces, a curved face havea substantially parabolic shape (as upper part), and a lower part thatcomprises two faces, which partially mimics a parabolic shape, but whichallows the lower reflector part to be relative shorter than when a pureparabolic lower part would be chosen. However, in other embodimentsespecially the radiation unit(s) comprise a lower (substantially flat)reflector part comprising a single face, and an upper reflector parthaving a parabolic-like shape, Hence, in some embodiments the radiationunit(s) comprise a lower reflector part with a face having anon-parabolic shape, such as a flat shape, and an upper reflector parthaving a parabolic-like shape. In a specific embodiment, the heatingelement may be configured on the centerline of the parabolic-like shapeand as close as possible to the focus of that parabolic-like shape; withespecially taking into account a minimal distance between the reflectorand the heating element.

It may not be optimal, and, depending on the design of the apparatus, itmay sometimes even not be possible, to solve the problem of splatteringfat and/or oil on the reflectors. Further, it appears to be difficult tomake the reflectors easily cleanable. First of all, the reflectors maytypically become so hot (easily 200-360° C.) that the fat will alreadyburn in before the user gets the chance to clean the reflectors.Secondly, the best reflectors are made from very reflective material,usually aluminum, and regularly cleaning these surfaces with brushes,sponges or other (abrasive) material will have a negative impact on thereflection coefficient.

It appears that using a (glass) shield is a better way to protect thereflectors, since the glass plates are easier to reach, and glass isalso better resistant against aggressive cleaning methods. Further, itmay protect a user from touching the radiation heater. One of theproblems to deal with when using glass shields is that most types ofglass block a significant part of the light spectrum, especially theinfrared part (above 3 micrometers) which is the most relevant forgrilling. A solution for this would be to use quartz glass (fusedsilica) which is significantly more translucent than regular glass inthe range of 3-4.5 micrometers. Surprisingly, it appears that thedifference in grilling result/time between quartz and regular glass isnot very large. Analyses showed that this is due to the fact that theglass heats up (due to the energy it receives from the blocked light),and can easily reach temperatures of 300-450° C. At this temperature, itstarts to radiate towards the food again, effectively reducing the realenergy losses. Hence, an aspect of the present invention is that when aprotective window is applied, this is especially not configured“substantially vertical”. Such orientation, the re-radiated heat doesnot reach the food in an optimal way. This results in reduced energyefficiency of the grill. The protective window is transmissive for IRradiation, i.e. it allows transmission of at least part of the IRradiation generated by the IR radiation heater. The phrase “transmissionof at least part of the IR radiation” may also refer to embodimentswherein some part of the IR wavelength range may be transmitted betterby the protective window than other parts of the protective window.

Hence, it is further suggested to arrange a protective window, such asthe glass, at an angle from the “substantially vertical orientation”. Byputting the glass shields (or other protective window) at an angle, itis possible to increase the amount of re-radiated energy from the glassthat reaches the food. This is because, at an angle, the so-called viewfactor increases. The larger the angle, the better the view factor (seealso below), and the more radiation will go through the protectivewindow (such as a glass shield) instead of being reflected on thesurface of the protective window (such as the glass surface) into thereflector again, but using large angles may also have a disadvantage asoil and/or fat from the food may drip more easily on the glass. Itappears that using the Hottel Crossed String Method for View Factor, theideal range for the angle will be between 0-60° (but at least largerthan 0° (i.e. not vertical), especially 10-45°, like 15-20°. Forinstance, already at a relatively small angle of 15°, the efficiencygain of the re-radiated energy is approximately 35%, resulting in atotal efficiency improvement of approximately 17.5% (assuming there-radiated energy is around 50% of the total energy reaching the foodsupport unit, which is a realistic assumption). At 45°, the gain is even˜50%. At higher angles the efficiency still gradually increases further,but the disadvantages (the glass becoming dirty more easily, and theassociated smoking) also become much more prominent. Especially, a lowerpart of the reflector, especially at the lower part edge, a tangent mayhave an angle γ (see FIG. 3b ) with a horizontal in the range of 10-45°,especially 10-40°, such as 15-35°.

Hence, in an aspect, the invention provides a radiation grill unitcomprising (i) a food support unit, and (ii) a radiation unit,especially comprising a reflector hosting an electrical IR radiationheater, wherein the radiation unit is configured to provide IR radiationin a direction of the food support unit, wherein the radiation unitfurther comprises a protective window which is transmissive for the IRradiation, wherein the protective window is arranged under an windowangle (β) selected from the range of 0<β≤60° relative to a normal toearth's surface. The phrase “relative to a normal to earth's surface”especially indicates a configuration during normal use of the radiationgrill unit.

Even more especially, the invention provides a radiation grill unitcomprising (i) a grill grid with bars, the grill grid comprising a foodsupport side and a radiation side, (ii) a radiation unit, especiallycomprising a reflector hosting an (electrical) IR radiation heater,wherein the radiation unit is configured to provide IR radiation in adirection of the radiation side of the grill grid, and (iii) a radiationgrill unit cavity configured to host a drip tray, wherein the radiationunit further comprises a protective window which is transmissive for theIR radiation, wherein the protective window is arranged under an windowangle selected from the range of 0<β≤60° relative to a normal to thegrill grid.

Especially, the protective window (essentially) closes off the reflectoropening.

As a (substantial) vertical orientation of the protective window may beless desired, here the angle of >0° relative to a normal to earths face,or in specific embodiments relative to a normal to the grill grid, isdefined. Again, this may especially apply to conditions during use ofthe radiation grill unit.

Especially, the window angle (β) selected from the range of 10≤β≤45°,even more especially the window angle (β) selected from the range of15≤β≥45°. As indicated above, these angles may provide an optimum withrespect to protection of the radiation heater and/or reflector and withrespect to efficiency of cooking (especially thus grilling) the food

As indicated above, in an embodiment the protective window comprisesglass, especially the protective window comprises glass ceramic. In yetanother embodiment, the protective window comprises quartz.

In yet a further specific embodiment, the protective window comprises aprotective window lower edge, wherein the radiation grill unit (isconfigured to) comprise(s) said drip tray, said drip tray comprising adrip tray face, and wherein the protective window lower edge isconfigured above the drip tray face (when the drip tray is configured inthe radiation grill unit cavity). Hence, any lipid droplet that may falldown at the protective window may, dependent upon the conditions,further travel under influence of gravity down to said protective windowlower edge and then fall down in the drip tray (if not vaporized orburned). Herein, the phrase “droplet falling down” may optionally alsorefer to a droplet splashing or spattering away.

Note that a lower part edge of the reflector may penetrate extend into)the grill cavity more than the upper part edge of the reflector.Assuming two oppositely arranged radiation units, the shortest distancebetween the lower part edges of the two opposite radiation units will ingeneral be shorter than the shortest distance between the upper partedges of the same two opposite radiation units. Especially, the lowerpart edge of the reflector may have a shortest (horizontal) distance toa central point in the grill cavity that is shorter than a shortest(horizontal) distance from the upper part edge of the reflector to thecentral point in the grill cavity.

The same may apply when a protective window is applied. A lower edge ofthe protective window may penetrate the grill cavity more than the upperedge of the protective window. Assuming two oppositely arrangedradiation units, the shortest distance between the lower edges of thetwo protective windows of the two opposite radiation units will ingeneral be shorter than the shortest distance between the upper edges ofthe same two protective windows (of these opposite radiation units).Especially, the lower edge of the protective window may have a shortest(horizontal) distance to a grill unit central point or grill unit bodyaxis in the grill cavity that is shorter than a shortest (horizontal)distance from the upper edge of the protective window to the grill unitcentral point or grill unit body axis in the grill cavity.

The angle may thus especially be chosen such that an inclined protectivewindow is obtained, which, when seen from a lower part (lower edge) ofthe protective window, inclines away from (a grill unit central point orgrill unit body axis of the) the grill cavity.

A common practical problem when building radiation grills according toprior art concepts is that the reflector(s) can become very hot. Withoutany cooling, they may become 450° C. or even higher. At suchtemperatures, aluminum (which is an ideal reflector material since ithas good reflective properties) may lose its strength. And even ifstrength (maintenance) was not a problem (e.g. by using a steel basematerial), such high temperatures may make it very difficult to complywith safety regulations that exist for domestic appliances, such as e.g.described in IEC-60335. Most of the prior art solutions do not seem topay attention to this aspect.

Herein, a solution to cool the reflectors, especially with naturalconvection is proposed. The air flow may be guided in such a way that itis used to improve the functionality of the grill. Especially, a channelbehind each reflector (unit) may be provided. With the free convectionthat originates from the hot, vertical surfaces in that area, an airflow may be created from below the reflectors, near the drip tray, toabove the reflectors, near the food support unit, especially the grillgrid. This has the advantage that the air is sucked in from a coollocation (the surface on which the appliance is standing), cooling thedrip tray along its path, and after exchanging heat with the reflectors,giving back part of this heat to the food in the form of hot air. Asnatural convection can be applied, this may add to user convenience,such as noise. It may also add to life time and ease of replacement ofparts.

Especially assuming a reflector with a length of ˜15-50 cm, such as30-40 cm, it appears to be advantageous when the smallest distancebetween the reflectors and the housing is between 5 and 25 mm to allowfor a stable, largely laminar flow. Furthermore, to substantiallyprevent that no obstructions exist for the airflow to move upwards, itis especially chosen that the cross section of the outlet opening may besubstantially larger than the cross-sectional area of the inlet opening.This may promote a stable, laminar flow and a high air speed around theinlet opening, where most cooling is required. In this way, it ispossible to achieve a heat-removing effect on the reflectors of at least0.2 Watts per square cm of reflector surface (assuming a reflectortemperature of 300° C.).

Hence, in an aspect, the invention provides a radiation grill unitcomprising (i) a food support unit, and (ii) a radiation unit,especially comprising a reflector hosting an electrical Flt radiationheater, wherein the radiation unit is configured to provide IR radiationin a direction of the food support unit, further comprising a radiationunit housing with a radiation unit housing cavity configured to host theradiation unit, wherein the radiation unit housing further comprises aconvection channel configured to facilitate free convection of air alongthe radiation unit. The radiation unit housing may herein also beindicated as heat shield. Even more especially, the invention provides aradiation grill unit comprising (i) a grill grid with bars, the grillgrid comprising a food support side and a radiation side, (ii) aradiation unit, especially comprising a reflector hosting an(electrical) IR radiation heater, wherein the radiation unit isconfigured to provide IR radiation in a direction of the radiation sideof the grill grid, and (iii) a radiation grill unit cavity configured tohost a drip tray, further comprising a radiation unit housing with aradiation unit housing cavity configured to host the radiation unit,wherein the radiation unit housing further comprises a convectionchannel configured to facilitate free convection of air along theradiation unit.

With such convection channel, a gas flow (air flow) may naturally begenerated, i.e. natural convection. Hence, energy consuming, spaceconsuming, and/or noisy fans or other devices like cooling means are notnecessary.

Note that the radiation unit housing may in an embodiment be a separatehousing within a larger housing, i.e. the radiation unit housing, or thegrill unit housing itself may be the radiation unit housing. Especially,the radiation unit housing comprise a convection channel configured tofacilitate free convection of air along the back side of the reflector(of the radiation unit).

In a further specific embodiment, the radiation unit housing comprises aradiation unit housing lower opening (herein also indicated as “loweropening”) and a radiation unit housing upper opening (herein alsoindicated as “upper opening”) defining a first end and a second end ofthe convection channel. The upper opening is closer to the food supportunit, especially a grill grid, than the lower opening. Especially, theradiation unit housing upper opening may be configured to facilitatedirecting a flow of air escaping from the radiation unit housing upperopening in the direction of the radiation side of the food support unit,especially a grill grid. Hence, especially the radiation unit isarranged at a non-zero distance from the radiation unit housing (whereinsuch convection channel, with an inlet and an outlet, may be available).This convection channel may be an elongated channel, as the radiationunit may also be an elongated unit.

Especially, the radiation unit housing upper opening comprises a crosssectional upper opening area (A1) and the radiation unit housing loweropening comprises a cross sectional lower opening area (A2). In yet afurther specific embodiment the convection channel has a ratio of thecross sectional upper opening area (A1) to the cross sectional loweropening area (A2) selected from the range of 0.8≤A1/A2≤4, even moreespecially 1≤A1/A2≤2. With dimension outside this range, flow may beless optimal. Hence, cooling may be worse and/or heating of the foodproduct/food support unit may be worse.

In yet a further embodiment, the radiation unit has a radiation unitlength (LR), wherein the radiation heater has a radiation heater length(LRH) and wherein the radiation unit housing cavity has a radiation unithousing length (LRUH), wherein 0.9≤LRH/LR<1, and wherein 0.9≤LR/LRUH≤1.In other words, the (electrical) radiation heater length is nearly aslong as its housing, the radiation unit; and, the length of theradiation unit is as long or nearly as long as its housing, theradiation unit housing.

Especially, the radiation grill unit may comprise a housing, wherein thehousing comprises a housing opening for influx of air. In embodiments,the housing comprises a housing bottom and a housing edge, wherein oneor more of the housing bottom and the housing edge comprise a housingopening for influx of air. Optionally, the grill unit, such as thehousing, may further include a heat sink. Again, the term “heat sink”may also refer to a plurality of heat sinks.

In yet a further aspect, the invention also provides a method forcooking a food product, the method comprising arranging the food productto the food support unit, especially a grill grid, of the (electrical)radiation grill unit and providing IR radiation to the food product. Inyet another aspect, the invention also provides a cooked food product,especially a grilled food product, obtainable with the method asdescribed herein and/or obtainable by grilling the food product with theradiation grill unit as described herein. Hence, one may for instancearrange the food product on a grill grid or attach to a hook or spit,etc.

In yet a further aspect, the invention also provides a food support unitper se, especially a grill grid with bars, wherein the bars have bardiameters (DB) and bar distances (PB), wherein the bar diameters (DB)are selected from the range of 1-4 mm, and wherein a ratio PB/DB betweenthe bar distances (PB) and bar diameters (DB) is selected from the rangeof 2-10.

In yet a further aspect, the invention also provides a drip tray per se,especially a drip tray comprising a drip tray face and a drip trayreservoir configured at an edge of the drip tray and configured to(temporarily) store a lipid comprising liquid, and wherein the drip trayface comprises collection means configured to guide the lipid comprisingfluid from the drip tray face to the drip tray reservoir.

Note that in general the drip tray and/or the food support unit,especially a grill grid, are removable items, which may be removedwithout the necessity of e.g. unscrewing (from the radiation grillunit).

As indicated above, the radiation grill unit is especially an electricalradiation grill unit with electrical (radiation) heaters. The radiationgrill unit may include a power regulation. Further, the radiation grillmay in embodiments not include a temperature regulation. Prior artsystems may include an energy storage (in the grill surface). If thetemperature of this storage is too high or too low, the thermostat willswitch the heating element on and off. In this invention, the radiationgrill unit does not necessarily include an energy storage and thereforedoes (advantageously not necessarily include a thermostat). Theradiation grill unit may only have a power regulation including theoptions off=0% and on=100% power. However, in further embodiments thepower regulation may also include (optional) settings with intermediatepowers (for example 25%, 50%, 75% of full power). Especially, theheating element will not switch on and off during grilling, althoughthis may of course also be possible in an embodiment. Hence, the grillunit may also include a power regulation configured for providing avariable power (to the radiation heater(s)).

The term “substantially” herein, such as in “substantially all light” orin “substantially consists”, will be understood by the person skilled inthe art. The term “substantially” may also include embodiments with“entirely”, “completely”, “all”, etc. Hence, in embodiments theadjective substantially may also be removed. Where applicable, the term“substantially” may also relate to 90% or higher, such as 95% or higher,especially 99% or higher, even more especially 99.5% or higher,including 100%. The term “comprise” includes also embodiments whereinthe term “comprises” means “consists of”. The term “and/or” especiallyrelates to one or more of the items mentioned before and after “and/or”.For instance, a phrase “item 1 and/or item 2” and similar phrases mayrelate to one or more of item 1 and item 2. The term “comprising” may inan embodiment refer to “consisting of” but may in another embodimentalso refer to “containing at least the defined species and optionallyone or more other species”.

Furthermore, the terms first, second, third and the like in thedescription and in the claims, are used for distinguishing betweensimilar elements and not necessarily for describing a sequential orchronological order. It is to be understood that the terms so used areinterchangeable under appropriate circumstances and that the embodimentsof the invention described herein are capable of operation in othersequences than described or illustrated herein.

The devices herein are amongst others described during operation. Aswill be clear to the person skilled in the art, the invention is notlimited to methods of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.Use of the verb “to comprise” and its conjugations does not exclude thepresence of elements or steps other than those stated in a claim. Thearticle “a” or “an” preceding an element does not exclude the presenceof a plurality of such elements. The invention may be implemented bymeans of hardware comprising several distinct elements, and by means ofa suitably programmed computer. In the device claim enumerating severalmeans, several of these means may be embodied by one and the same itemof hardware. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage.

The invention further applies to a device comprising one or more of thecharacterizing features described in the description and/or shown in theattached drawings. The invention further pertains to a method or processcomprising one or more of the characterizing features described in thedescription and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order toprovide additional advantages. Furthermore, some of the features canform the basis for one or more divisional applications.

Especially, the invention provides a radiation grill unit comprising (i)a grill grid with bars, the grill grid comprising a food support sideand a radiation side, (ii) a radiation unit, especially comprising areflector hosting an (electrical) IR radiation heater, wherein theradiation unit is configured to provide IR radiation in a direction of(the radiation side of) the grill grid, and optionally (iii) a radiationgrill unit cavity configured to host a drip tray.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying schematic drawings in whichcorresponding reference symbols indicate corresponding parts, and inwhich:

FIGS. 1a-1d schematically depict some aspects;

FIGS. 2a-2f schematically depict some aspects, especially with respectto grid dimensions;

FIGS. 3a-3b schematically depict some aspects, especially with respectradiation units;

FIGS. 4a-4c schematically depict some aspects, especially with respectto a protective window;

FIGS. 5a-5b schematically depict some aspects, especially with respectto convection channel;

FIGS. 6a-6c schematically depict some aspects, especially with respectto the drip tray; and

FIGS. 7a-7c schematically depict some aspects; especially with respectto the radiation units and variations thereon.

Where applicable, the (schematic) drawings are not necessarily on scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1a schematically depicts an embodiment of a radiation grill unit 1.The radiation grill unit 1 comprises (i) a food support unit 100, hereespecially a grill grid 1100 with bars 110 (not individually depicted;see however below), (ii) a radiation unit 200 and (iii) a radiationgrill unit cavity 3. The grill grid 1100 comprises a food support side101 and a radiation side 102. By way of example, a food product 2 isdepicted, which is arranged on the food support side 101 of the grillgrid 1100. The radiation unit 200 comprises a reflector 210 hosting an(electrical) IR radiation heater 220. The reflector 210 comprises areflector opening 223. For clarity reasons, the electricalinfrastructure to provide power to the IR radiation heater 220 is notdepicted. However, this is known to the person skilled in the art. Alsoa housing is not depicted for clarity reasons.

The radiation unit 200 is configured to provide IR radiation 201 in adirection of the radiation side 102 of the grill grid 1100. Here, by wayof example only one radiation unit 200 is depicted. In general, at leasta single set of two radiation unit 200 is applied, each providingradiation from opposite sides relative to the radiation grill unitcavity, and each configured to provide IR radiation 201 in a directionof the radiation side 102 (see also below). Further, the radiation grillunit cavity 3 configured to host a drip tray 300, Here, the drip tray isindicated to be present. However, the drip tray 300 is in general aremovable item (like in general also the grill grid 1100 is).

Reference 311 indicates an edge of the drip tray 300. Within the edge(s)311 of the drip tray, lipid droplets, indicated with reference 7, may becollected (see also below).

FIG. 1b schematically depicts a top view of the grill unit 1. Reference221 indicates an axis of elongation of the IR radiation heater 220. Asindicated above, in general the IR radiation heater 220 comprises a bar.As FIG. 1b shows, the grid 1100 especially refers to a 1D array of bars110, and not to a 2D array of bars (with e.g. two sets of bars which areperpendicularly arranged to each other). References 116 and 117 indicatethe ends of the bars 110 of the grid 100. At those ends, there may beconnecting means to provide the set of parallel bars 110. Theseconnecting means (having especially a length of about LG, see below) mayalso comprise bars. Note however, that when perpendicular connectingmeans are available, those means may be limited in number, such as only2. Would intermediate connecting means (having especially a length ofabout LG, see below) be used, this number will in embodiments be smallerthan the total number of bars such as 50% or less. For instance theremay be less than 2 intermediate connecting means, like no intermediateconnecting means. Herein, intermediate connecting means are not depictedas they may especially be absent. Hence, in embodiments the grill gridessentially consists of an (1D) array of parallel arranged grid bars

Reference 1000 indicates a housing of the grill unit 1. Reference LRindicates the length of the radiation unit 100; reference LRH indicatesthe length of the IR radiation heater, which will in general onlyslightly smaller than the length LR of the radiation unit 100; referenceLG indicates the length of grid 100; and reference WG indicates thewidth of the grid. The area WG*LG will (approximately) be thecross-sectional area of the grill grid 1100. Note that substantially allIR radiation, or especially substantially all direct IR radiation mayimpinge on the radiation side of the grill grid (and is thusdistribution of this cross-sectional area). The plane of the grill grid1100 is also indicated with reference 105. Note in FIG. 1b that the bars110 are perpendicular to the IR radiation heater 110. Or, the grill bars110 are in a plane parallel to the axis of elongation 221, with the barsperpendicular to such axis.

FIG. 1b also shows connecting means 1111 (having especially a length ofabout LG, see below), which may in an embodiment also comprise bars. Theconnecting means 1111, at the ends of the bars, provide together withthe bars the grill grid. Note however, that when perpendicularconnecting means are available, those means may be limited in number,such as only 2. As indicated above, would intermediate connecting means(having especially a length of about LG, see below) be used, this numberwill in embodiments be smaller than the total number of bars such as 50%or less. FIG. 1b shows an embodiment without intermediate connectingmeans. The bar ends are all connected to both connecting means. In thisway, a 1D array of bars can be provided.

FIGS. 1c-1d schematically depict some alternative embodiments, whereinreference 1200 indicates a hook as embodiment of the food support unit100, and wherein reference 1300 indicates a spit or skewer as embodimentof the food support unit 100. In both examples a food product 2 isarranged to the food support unit 100.

FIG. 2a schematically depicts in more detail the grill grid 1100, againwith by way of example a piece of food (i.e. food product 2). FIG. 2a isa top view; FIG. 2b schematically depicts a side view, indicating thepitch or distance between the grill bars 110, which is indicated withreference PB (see FIG. 2b ). The diameter of the bars 110 is indicatedwith reference DB (see FIG. 2b ). Especially, the bars HO have bardiameters DB and bar distances PB, wherein the bar diameters DB areselected from the range of 1-4 mm, and a ratio PB/DB between the bardistances PB and bar diameters DB is selected from the range of 2-10.The length of the bars 110 is indicated with reference LB (which cansubstantially be identical to the width of the grid WG).

A number of experiments were performed, of which some data are indicatedbelow:

Thickness Pitch Absence Direction of bars of bars between bars of smokeLongitudinal 2.5 mm 13 + Perpendicular 2.5 mm 13 ++ Perpendicular   3 mm17 ++ Perpendicular   4 mm 13 +/− Perpendicular   6 mm 13 − (∩-shape)

Perpendicular bars with thicknesses in the range of 3 mm and a pitch of17 mm gave the best results. Further, it appears that better results canbe obtained with perpendicular bars. Here, perpendicular bars are barsthat are “perpendicular” to an elongated radiation heater 220 (see FIG.1b ).

FIG. 2c schematically an embodiment wherein the bars 110 comprisesloping parts 115 configured to facilitate dripping of a lipid droplet 7(not indicated in this schematic drawing, but see other drawings) intothe drip tray (see also other drawings), wherein especially the slopingparts 115 are configured at one or more of a position within 0-10% and aposition within 90-100% of the bar length LB. The bars 110 have a firstend 116 and a second end 117 (defining the length of the bar LB, seealso FIG. 2a ), at end parts 112 and a bar support part 111 in between.On the bar support part 111 a food product may be arranged. Here, inthis schematic embodiment the sloping parts 115 are comprised by curvedparts 113, which are in this embodiment arranged between the bar supportpart and the end parts 112. The intermediate part, between the curvedparts 113, is herein also indicated intermediate part 119. On thisintermediate part the food product 2 can be arranged. The onset of thecurved parts at the bars 110 at the radiation side 102 is indicated withreference 114. Especially at this position liquid lipid may gather, form(larger) droplets and fall down due to gravity. The length between thesloping parts 115 is indicated with reference SPL. Especially, thislength SPL is shorter than the width of the drip tray 300 (see also FIG.2e ). In FIGS. 2c (and 2 d) the bars 110 comprise intermediate parts 119which are arranged lower relative to the bar end parts. This mayadvantageously automatically prevent arranging food products too closeto the edge of the grill grid. FIGS. 2c & 2 d show curvatures in thebars relative to a length axis of the bar(s).

FIG. 2d schematically depicts a specific embodiment of the drip tray300, wherein the bars 110 comprise bar curves 113 which provide thesloping parts 115. Liquid material may migrate in a direction away fromthe grid ends 116,117 to the middle. Dripping in the drip tray maythereby be facilitated and dripping on a radiation unit, if possible inthe configuration, is reduced or prevented. Reference 131 indicate ahandle. In embodiments, a user may get the handle(s) and place or removethe grill grid 1100 in the grill unit.

FIG. 2e schematically depicts a further embodiment, wherein it can beseen that the width of the tray 300, indicated with reference WT may besmaller than the smallest radiation unit distance, which is indicatedwith reference WRU (which is here especially the distance between loweredges 231 of the optional protective windows, indicated with reference230), but may be chosen such that lipid droplets 7 may fall in the driptray 300 (i.e. SPL<WT). FIG. 2e , and other figures, schematicallydepicts an embodiment wherein a set of two (oppositely arranged)radiation units 200 is applied.

For instance, in embodiments such as schematically depicted in e.g.FIGS. 2c-2f , SPL may be in the range of 160-210 mm, WRU may be in therange of 170-230 mm, and WT may be in the range of 180-230. Especially,WT>WRU>SPL. Note that in the embodiment schematically depicted in FIG.2e , WT<WRU; however, this may thus also be the opposite, to furtherfacilitate dripping in the drip tray 300 (see FIG. 3a ).

FIG. 2f schematically depicts a 3D figure of an embodiment of the grillunit 1. As indicated above, reference 230 indicates a protection window(see below).

The radiation grill unit cavity may at two edges be confined by edges.For instance, referring to FIG. 2e , the grill unit cavity 3 maysubstantially be confined by (two) radiation units 200 and by (two)walls or shields. FIG. 2f shows a 3D view; the front of the grill unit 1may thus include a wall (the housing 1000 is drawn such that theinterior can be seen). Especially, these walls are above the drip tray;optionally a reservoir may extend beyond such wall (when seen from thecavity 3; see also below)). In FIGS. 2e and 2f two radiation units, eachat one side of the cavity is schematically depicted. Optionally, two ormore sets of such radiation units may be applied, with each setradiation unit at both sides of the cavity (or of the drip tray).

Linear heaters radiate their (infrared) energy in all directions.However, the energy is only needed at the grill surface (the grid). Allother parts of the grill should receive as little energy as possible,since part of the energy that those parts receive will be transformedinto heat, which has to be cooled away to prevent excessive temperaturerise. The most important part in the grill that should be protected fromradiation is the drip tray. This is the part that collects the fatdripping from the grilled food. When the drip tray becomes too hot(above approx. 150° C.), the fat starts to decompose (burn) and producesmoke. Smoke prevention is the main goal of the grill under discussion,so this needs to be avoided at any time. However, not only direct beamsto the drip tray should be avoided. Beams that hit the oppositereflector can in certain circumstances be reflected downwards and reachthe drip tray indirectly. Therefore, the goal is to prevent any infraredrays from hitting the opposite reflector. Traditionally, a reflectorwhich has a predominantly parabolic shape (in cross section) would bechosen to convert omnidirectional radiation into a focused parallelbeam. However, in the grill of the present invention, a parabolic shapewith the desired optical functionality would need to be much too big tofit into the appliance. Especially the lower parts of the reflectorwould be in the path of the dripping fat.

Therefore, it in embodiments it is supposed to tweak the parabolicshape: on the bottom, the parabolic shape was replaced by straightsegments with the same “shadow effect” for the opposite reflector, butmuch more compact; see FIG. 3a . Herein reference 211 indicates a lowerpart of the reflector 210 and reference 212 indicates a lower part edge;reference 213 indicates an upper part of the reflector 210 and reference214 indicates an upper part edge. The lower part 211 and the upper part213 may together form the reflector 210. The reflector may comprise (atthe inner side) an aluminum coating. The shortest distance between theradiation units 200 is indicated with reference WRU, here especially thedistance between the lower part edges 212 of the two oppositely arrangedradiation units 200. Reference 307 indicates schematically collected(liquid) lipid (material), including optionally other material likecarbon, food residues, water etc. etc. FIG. 3a also shows that a centralaxis or axis of elongation 221 of the radiation heater 220 of a firstradiation unit (here the left one) is configured below a line throughthe upper reflector part edge 214 of the radiation heater 220 of asecond radiation unit (here the right one) and the lower reflector partedge 212 of the first radiation unit. Of course, in a furtherembodiment, the entire radiation heater is below such line (thus eventhe upper edge of the radiation heater is below such line).

To achieve this “shadow effect”, a few aspects must be carefully chosenin the design, especially with respect to the (relative) dimensions ofthe reflector. Looking at FIG. 3b , the following can be defined asspecific embodiments:

The horizontal distance between the IR radiation heater 220 and thelower part edge 212 of the reflector 210 is defined as a, the verticaldistance between these same points is b. The horizontal distance betweenboth radiation heaters 220 is defined as c. The horizontal distancebetween the IR radiation heater 220 and the upper part edge 214 of thereflector 210 is defined as e. Ideally the relation between thedimensions should be:a/b=(c−e)/d  Equation 1Or, rewritten:a×d=b(c−e)  Equation 2However, in practice, it can be difficult to achieve this exactrelation, e.g. when the design needs to remain compact or other (design)requirements have to be fulfilled. In order to achieve more designfreedom, some deviation from the relation described in equation 1 can beallowed. Our experiments have shown that especially good results may beobtained between about:0.8≤(a×d)/(b(c−e))≤1.2  Equation 3

Note that the reflector 210 may also be configured with a lower part 211with more than two faces or with a lower part including only one face.Further, the lower part 211 of the reflector, especially at the lowerpart edge 212 a tangent may have an angle γ with a horizontal in therange of 10-45°, especially 10-40°, such as 15-35°.

FIG. 4a schematically depicts an embodiment wherein the radiation unit200 further comprises a protective window 230 which is transmissive forthe IR radiation 201. Especially, the protective window 230 is arrangedunder an window angle β selected from the range of 0<β≤60° relative to anormal to the grill grid 1100, even more especially selected from therange of 10≤β≤45°, such as 15≤β≤45°. Especially, the protective window230 (essentially) closes off the (elongated) reflector opening 223.

The protective window 230 comprises a protective window lower edge 231.Further, the radiation grill unit 1 comprises here said drip tray 300.The protective window lower edge 231 may be configured above the driptray face 301/drip tray 300. Note that in this schematic drawing this isnot the case (however this is the case in FIG. 5a ).

Note that the drip tray 300 in this invention is especially a removabledrip tray, which can be slided into the radiation grill unit (such as inthe housing 1000), and can be removed for e.g. cleaning.

The (smokeless) grill is designed to minimize the heat absorption by thegrilling chassis or housing. This may amongst others be achieved byplacing the heater at the sides of the chassis behind a glasscover/shield. Due to this placement a conventional heater—like a metalsheathed heater—may not (always be) possible due to its power/length.Thus especially a design is chosen to use heater wire wrapped around aelectrical insulated coil, such as amongst others defined above. Thiscoil can e.g. be made of quartz to withstand the high temperatures,although also other materials may be especially be chosen such as aceramic material, like ceramic alumina. Such ceramic materials maywithstand even higher temperatures. This design is able to generate therequired 1000 W or so per 30 cm length available. A positive side effectis its fast heat up time. This heating coil wrapped around a quartz coilis only one of the three parts of the heater subassembly. The secondpart is the reflector placed around the heater at the rear side. Thisreflector is used to ‘aim the heat’ as good as possible towards thegrilling area (and not to the chassis). The third part is the optional(glass) cover or window (made out of quartz, robax (glass ceramic) orother (substantially) zero expansion glasses or (aluminum-)borosilicateglasses), used to prevent spattering of meat juices onto the reflectoror heater (clean-ability and performances). As indicated herein, theprotective window may also be glass ceramic.

When the heater is powered the heating wire will increase intemperature, but because it's in solid contact with the quartz core orceramic core this core will heat as well and will reach similartemperatures as the heating wire. Thus the heater consists of tworadiation sources: the heating wire and the quartz coil or ceramic coil.The former will emit like a gray emitter. Quartz acts as a gray emittertoo, but due to its transparency the radiation takes an odd form. Hardlyany radiation can be emitted in the 1-4 micron range. The real emittingstarts at 4 micron. The heating coil will transmit continuously.Especially, the heater includes a ceramic coil.

This spectrum is emitted direct—or via the reflector—towards thegrilling area. But due to its quartz core a major part of the spectrumis located after the 4 micron. This implies—depending on the used glassshield—a major part of the energy is absorbed by the shield, heating theshield and resulting into a second heat source. But this heat source isnot aimed by a reflector, thus the radiation is (assumed) randomlydistributed. This means only a part is radiated towards the grill areaand is called the view factor from shield to grill surface. Calculatingthis view factor results in 0.37 (thus 37% of the radiated energy of theshield reaches the grill surface directly. The other 63% is interceptedby the chassis and most likely absorbed or reflected at such smallangles it will not couple with the food.

As shown in the picture above approx. 50% of the energy radiated fromthe heater reaches the grill surface direct—if reflector is designedwell—and 50% is absorbed by the glass shield. From this latter 50%, 37%(thus 50%*37%=18.5%) reaches the grill surface resulting in an overallefficiency of 68.5%. Better efficiencies can be achieved by increasingthe view factor by tilting the glass a bit. The view factor iscalculated by means of Hottel's string rule and looks like the curve inFIG. 4c : Fsa=view factor shield to grill area; and a=angle (0° meansperpendicular to grill surface, and 90° is in same plane as grill area).

Thus placing the shield at an angle of 30° enhances the view factor from0.37 to 0.63, resulting into 82% efficiency. Note that thesecalculations assume that: (1) the reflector is optimal (100% of heaterspectrum aimed at grill surface); and (2) the absorbed energy of theglass shield is emitted (except some convection losses), but is not lostvia the chassis (suspension of the glass) or additional cooling of theglass shield).

Reference I indicates the radiation emitted by the quartz tube;reference II indicates the radiation emitted by the coil; reference IIIindicates the total emission of the heater; reference IV indicates themeasured data which substantially confirm the curve III. On the x-axisthe wavelength in μm is indicated; on the y-axis relative intensitiesare indicated.

Note that a lower part edge of the reflector may penetrate the grillcavity more than the upper part edge of the reflector. Assuming twooppositely arranged radiation units, the shortest distance between thelower part edges of the two opposite radiation units will in general beshorter than the shortest distance between the upper part edges of thesame two opposite radiation units. Especially, the lower part edge ofthe reflector may have a shortest (horizontal) distance to a centralpoint 130 in the grill cavity that is shorter than a shortest(horizontal) distance from the upper part edge of the reflector to thecentral point 130 in the grill cavity.

FIG. 5a schematically depicts an embodiment (in cross-section)comprising a radiation unit housing 250 with a radiation unit housingcavity 251 configured to host the radiation unit 200. The radiation unithousing 250 is constructed in such a way that this radiation unithousing 250 further comprises a convection channel 252 configured tofacilitate free convection of air along the radiation unit 200. Flow ofair is indicated with reference 270.

The radiation unit housing 250 comprises a radiation unit housing loweropening 255 and a radiation unit housing upper opening 256 defining afirst end and a second end of the convection channel 252. Relativecooler air enters radiation unit housing lower opening 255, is beingheated, rises, and leaves the convection channel 252 radiation unithousing upper opening 256 (in the direction of the radiation side 102 ofthe grill grid 1100. This may lead to an additional heating. Here, theradiation unit housing 250 comprises a convection channel 252 configuredto facilitate free convection of air along the (back side (reference215) of the reflector (of the) radiation unit 200. Note that inembodiments there may be a separate radiation unit housing 250integrated in housing 1000, whereas in other embodiments the housing1000 may include the functionality of a radiation unit housing (whichmay in fact be the case in the schematically depicted embodiment of FIG.5a ). Here, but this may also apply to other embodiments, the housing1000 further comprises a housing opening 8 for influx of air.

FIG. 5b schematically depicts a view of this housing when seen from thefood support unit, especially seen from the grill grid, to the radiationunit 200. The radiation unit housing upper opening 256 comprises a crosssectional upper opening area (A1) and the radiation unit housing loweropening 255 comprises a cross sectional lower opening area (A2).Experimentation showed that better cooking results (cooked food productquality, cooking time, efficiency) were obtained when the convectionchannel 252 has a ratio of the cross sectional upper opening area (A1)to the cross sectional lower opening area (A2) selected from the rangeof 0.8≤A1/A2≤4.

FIGS. 6a-6c schematically depicts some embodiments of a drip tray 300.Such drip tray may be used in the present grill unit 1, but may also beused in other cooking systems. In the present invention, the drip tray300 is especially configured in the radiation grill unit cavity 3 out ofthe line of sight of direct IR radiation 201 from the radiation heater220, see FIGS. 1a, 2e-2f, 3a, 4a, and 5a . The drip tray 300 comprises adrip tray face 301 and a drip tray reservoir 302 configured at an edge311 of the drip tray 300. The drip tray reservoir is especiallyconfigured to (temporarily) store a lipid comprising liquid 307.Further, here the drip tray face 301 comprises collection means 303configured to guide the lipid comprising fluid 307 from the drip trayface 301 to the drip tray reservoir 302. Here the collection means 303include a V-shaped drip tray face 301 (and a collection channel 304).This (these) facilitate collection of liquid in the drip tray reservoir302. The drip tray face 301 may include one or more flat parts, but mayalternatively or additionally also include one or more curved parts. Inthe herein depicted embodiment, two drip tray reservoir 302 may beavailable. In use, especially the drip tray 300 is arranged below thefood support unit, such as a grill grid, with the radiation units atboth sides, and with the drip tray reservoir at the other edges (in FIG.6a this would imply that the radiation units are configured at the leftand the right side/edge of the drip tray 300). FIG. 6b schematicallydepicts a 3D view of an embodiment of the drip tray 300 of FIG. 6a .FIG. 6c schematically depicts an embodiment with one or more curvedparts. Here a drip tray face 301 is applied with a kind of saddle shape.The saddle shape is indicated with reference 306.

FIG. 6a schematically depicts a perspective top view of the drip tray300. When arranged in the radiation grill unit 1, the radiation unitsmay be at the left and right side, and edges of the cavity 3 may be overthe reservoir(s) 302, and may especially over the drip tray face 301,but close to the reservoir(s) 302. In this way, dripping liquid may fallon the chip tray face 301 and be collected via collection means 303 intothe reservoir 302.

FIGS. 7a-7c schematically depict some aspect of the radiation unitagain. FIG. 7a schematically depict a number of the configuration of theradiation unit 200 that were investigated. Here, five configurations aredepicted (H3, H4, H5.0, H5.2, H7.2). The position of the radiationheater of configurations H4 and H5.0 overlap. Here, all radiation unitscomprise a protective window 320. Below some data are given of reflectorshapes that were tested/simulated, of which some are depicted in FIGS.7a-7c .

H 3 H 4 H 5.0 H 5.2 H 6.1 H 7.2 Construction Glass Angle β 0° (vert.) 0°(vert.) 15° 15° 23° 20° a*d/(b*(c − e)) 6.0 −2.8 4.0 1.0 0.6 1.0 WRUminimal minimal minimal minimal maximal intermediate Prototype TestingWattage high high medium low low low Grill + + ++ +++ + +++ PerformanceDrip Tray −−− −− − + ++ +++ Temperature Simulation values With glass +reflection on glass 10% + absorption 30% Watt at grid ++ ++ ++ Driptray + ++ +++ staying cool Remarks: small parabolic first improved smallWRU < grid inefficient shaped glass at reflector reflector width -->reflectors, reflectors, angle shape with special active lower (straightmax. grid with ventilation reflector lower WRU drip necessary. part edgereflector positioning Vertical lower than part) not above window heatingthe glass element

FIG. 7b shows a 2D-simulation (only direct radiation) perpendicular tothe heating element of a reflector without a straight lower reflectorpart (such as configuration H5.0) that gives a shadow on the reflectoron the opposite side. In FIG. 7b , the radiation of only one heatingelement is visible (i.e., illustrated). Furthermore, as shown in FIG. 7b, a part of the direct radiation from the heating element of the firstreflector will be reflected via the second reflector on the oppositeside into the drip tray, which will be heated up and may cause smokeafter a while. In contrast, FIG. 7c shows a 2D-simulation (only directradiation) perpendicular to the heating element of a reflector with astraight lower reflector part (such as configuration H5.2) that gives ashadow on the reflector on the opposite side. In FIG. 7c , there will beno direct radiation that ends up in the drip tray. Therefor the driptray, as shown in the embodiment of FIG. 7c , may stay much cooler.Smoke formation may be reduced or prevented.

Many of the drawings above elucidated different aspects that are notnecessarily combined. For instance information about a drip tray mayrelate to the specific drawing but such embodiment of the drip tray mayalso be applied in other embodiments, for instance where an optimizedgrill grid is described and/or depicted, or wherein an optimizedconvection system is described and/or depicted, or wherein an optimizedprotective window configuration is described and/or depicted, or whereinan optimized configuration of a set of radiation units is describedand/or depicted, etc.

The invention claimed is:
 1. A radiation grill unit for grilling food inan open grill arrangement, the radiation grill unit comprising: (i) afood support unit having a cross-sectional area; (ii) two radiationunits, wherein each of the two radiation units comprises a reflector andan infrared (IR) radiation heater hosted within an inner region of thereflector, wherein the reflector includes an upper part and a lowerpart, the upper part having a substantially parabolic-shaped surface andan upper part edge, and the lower part having at least one substantiallystraight surface and a lower part edge, wherein the upper part edge andthe lower part edge define a reflector opening, wherein the IR radiationheater is configured at a first depth below the lower part edge and at asecond depth below the upper part edge, wherein the second depth isgreater than the first depth, wherein the IR radiation heater is furtherconfigured at a first horizontal distance from the lower part edge andat a second horizontal distance from the upper part edge, and whereinthe second horizontal distance is smaller than the first horizontaldistance, each of the two radiation units further being configured toprovide IR radiation, via the IR radiation heater, through the reflectoropening in a direction of the food support unit; (iii) a radiation grillunit cavity configured to host the two radiation units opposite eachother at opposite ends of the radiation grill unit cavity, belowopposite side edges the food support unit, wherein the lower part edgeof the reflector of each respective radiation unit is spaced closer to acenter point of the radiation grill unit cavity than the upper part edgeof the reflector of the respective radiation unit, and wherein IRradiation from the two radiation units is uniformly distributed over thecross-sectional area and edges of the food support unit; and (iv) a driptray, wherein the drip tray is hosted within the radiation grill unitcavity in between the two radiation units below the lower part edge ofthe lower part of the reflector of each respective radiation unit,wherein the at least one substantially straight surface of the lowerpart of the reflector of each respective radiation unit is positioned atan angle relative to horizontal, to block rays of IR radiation thatwould otherwise be directed towards the drip tray and the reflector ofthe opposite radiation unit of the two radiation units and thus renderthe drip tray and the reflector of the opposite radiation unit of thetwo radiation units out of a line of sight of direct IR radiation fromthe IR radiation heater of a respective radiation unit, further whereinthe drip tray comprises a drip tray face and at least one drip trayreservoir, and wherein the at least one drip tray reservoir isconfigured at a side edge of the drip tray to store a lipid comprisingliquid.
 2. The radiation grill unit according to claim 1, wherein (i)the food support unit comprises a grill grid with bars, wherein thegrill grid comprises a food support side and a radiation side or (ii)the food support unit comprises one or more selected from the group of aspit, a skewer, a clamp, and a hook.
 3. The radiation grill unitaccording to claim 1, wherein each radiation unit of the two radiationunits further comprises the reflector hosting an electrical IR radiationheater.
 4. The radiation grill unit according to claim 1, wherein (i)the food support unit comprises a grill grid with a one-dimensionalarray of bars arranged in parallel, wherein the grill grid comprises afood support side and a radiation side, and (ii) each radiation unit ofthe two radiation units is further configured to provide IR radiation ina direction of the radiation side of the grill grid.
 5. The radiationgrill unit according to claim 1, wherein the drip tray face comprises acentral collection channel in fluid connection with the at least onedrip tray reservoir.
 6. The radiation grill unit according to claim 1,wherein the drip tray reservoir has a storage volume for the lipidcomprising liquid in a range of 50-350 ml.
 7. The radiation grill unitaccording to claim 1, wherein the drip tray face comprises a curvatureconfigured to guide the lipid comprising fluid from the drip tray faceto the at least one drip tray reservoir.
 8. The radiation grill unitaccording to claim 1, wherein the drip tray face has a saddle-likeshape, and wherein the at least one drip tray reservoir comprises two ormore drip tray reservoirs at side edges of the drip tray.
 9. Theradiation grill unit according to claim 4, wherein all IR radiationprovided by each radiation unit of the two radiation units is directedto the radiation side of the grill grid.
 10. The radiation grill unitaccording to claim 1, further comprising: a protective window,transmissive for the IR radiation, for each of the two radiation units,wherein the protective window is arranged in front of the reflectoropening of a respective radiation unit, between the respective radiationunit and radiation grill unit cavity, the protective window furtherbeing at an angle (β) relative to a normal to a food support surface ofthe food support unit, with β>0°, and wherein the protective windowfurther comprises a lower edge that is (a) configured above the driptray face, and (b) horizontally extends within an inner horizontal widthdimension of the drip tray face more than an upper edge of theprotective window.
 11. The radiation grill unit according to claim 10,wherein the protective window comprises one selected from the groupconsisting of glass, glass ceramic, and quartz.
 12. The radiation grillunit according to claim 1, wherein the food support unit comprises agrill grid with a one-dimensional array of bars arranged in parallel,wherein the grill grid comprises a food support side and a radiationside, wherein the bars each have a bar diameter (DB) and a bar distance(PB) between adjacent bars, wherein the bar diameter (DB) comprises adiameter in a range of 1-4 mm, and wherein a ratio PB/DB between (i) thedistance (PB) between adjacent bars and (ii) the bar diameter (DB) iswithin a range of 2≤PB/DB≤10.
 13. The radiation grill unit according toclaim 1, further comprising two convection channels, each convectionchannel configured to facilitate free convection of air, from below thelower part edge to above the upper part edge of the reflector of arespective radiation unit of the two radiation units, along a back sideof the reflector of the respective radiation unit opposite to a frontside of the reflector that reflects the IR radiation in the direction ofthe food support unit.
 14. A method for cooking a food product via theradiation grill unit according to claim 1, the method comprising:arranging the food product onto the food support unit of the radiationgrill unit; and providing IR radiation, via the two radiation units ofthe radiation grill unit, to the food product.
 15. The radiation grillunit according to claim 1, wherein a location of the drip tray reservoiris behind and/or below lower edges of the radiation grill cavity. 16.The radiation grill unit according to claim 1, wherein the food supportunit comprises a grill grid with a one-dimensional array of barsarranged in parallel, each bar having a bar length with two ends, anintermediate portion, and two sloping portions configured to facilitatetransport of lipids in a direction of a middle of the bar, and whereineach sloping portion is in between a respective end of the bar and theintermediate portion, the intermediate portion being located in themiddle of the bar.
 17. A radiation grill unit for grilling food in anopen grill arrangement, the radiation grill unit comprising: (i) a foodsupport unit having a cross-sectional area; (ii) two radiation units,wherein each of the two radiation units comprises a reflector and aninfrared (IR) radiation heater hosted within an inner region of thereflector, wherein the reflector includes an upper part and a lowerpart, the upper part having a substantially parabolic-shaped surface andan upper part edge, and the lower part having at least one substantiallystraight surface and a lower part edge, wherein the upper part edge andthe lower part edge define a reflector opening, wherein the IR radiationheater is configured at a first depth below the lower part edge and at asecond depth below the upper part edge, wherein the second depth isgreater than the first depth, wherein the IR radiation heater is furtherconfigured at a first horizontal distance from the lower part edge andat a second horizontal distance from the upper part edge, and whereinthe second horizontal distance is smaller than the first horizontaldistance, each of the two radiation units further being configured toprovide IR radiation, via the IR radiation heater, through the reflectoropening in a direction of the food support unit; (iii) a radiation grillunit cavity configured to host the two radiation units opposite eachother at opposite ends of the radiation grill unit cavity, belowopposite side edges the food support unit, wherein the lower part edgeof the reflector of each respective radiation unit is spaced closer to acenter point of the radiation grill unit cavity that the upper part edgeof the reflector of the respective radiation unit, and wherein IRradiation from the two radiation units is uniformly distributed over thecross-sectional area and edges of the food support unit; (iv) a driptray, wherein the drip tray is hosted within the radiation grill unitcavity in between the two radiation units below the lower part edge ofthe lower part of the reflector of each respective radiation unit,wherein the at least one substantially straight surface of the lowerpart of the reflector of each respective radiation unit is positioned atan angle relative to horizontal, to block rays of IR radiation thatwould otherwise be directed towards the drip tray and the reflector ofthe opposite radiation unit of the two radiation units and thus renderthe drip tray and the reflector of the opposite radiation unit of thetwo radiation units out of a line of sight of direct IR radiation fromthe IR radiation heater of a respective radiation unit, further whereinthe drip tray comprises a drip tray face and at least one drip trayreservoir, wherein the at least one drip tray reservoir is configured ata side edge of the drip tray to store a lipid comprising liquid, andwherein the drip tray face comprises collection means configured toguide the lipid comprising fluid, via migration or drainage, from thedrip tray face to the drip tray reservoir; and (v) a protective window,transmissive for the IR radiation, for each of the two radiation units,wherein the protective window is arranged in front of a reflectoropening of a respective radiation unit, between the respective radiationunit and radiation grill unit cavity, the protective window furtherbeing at an angle (β) relative to a normal to a food support surface ofthe food support unit, with β>0°, and wherein the protective windowfurther comprises a lower edge that is (a) configured above the driptray face, and (b) horizontally extends within an inner horizontal widthdimension of the drip tray face more than an upper edge of theprotective window.
 18. A radiation grill unit for grilling food in anopen grill arrangement, the radiation grill unit comprising: (i) a foodsupport unit having a cross-sectional area; (ii) two radiation units,wherein each of the two radiation units comprises a reflector and aninfrared (IR) radiation heater hosted within an inner region of thereflector, wherein the reflector includes an upper part and a lowerpart, the upper part having a substantially parabolic-shaped surface andan upper part edge, and the lower part having at least one substantiallystraight surface and a lower part edge, wherein the upper part edge andthe lower part edge define a reflector opening, wherein the IR radiationheater is configured at a first depth below the lower part edge and at asecond depth below the upper part edge, wherein the second depth isgreater than the first depth, wherein the IR radiation heater is furtherconfigured at a first horizontal distance from the lower part edge andat a second horizontal distance from the upper part edge, and whereinthe second horizontal distance is smaller than the first horizontaldistance, each of the two radiation units further being configured toprovide IR radiation, via the IR radiation heater, through the reflectoropening in a direction of the food support unit; (iii) a radiation grillunit cavity configured to host the two radiation units opposite eachother at opposite ends of the radiation grill unit cavity, belowopposite side edges the food support unit, wherein the lower part edgeof the reflector of each respective radiation unit is spaced closer to acenter point of the radiation grill unit cavity than the upper part edgeof the reflector of the respective radiation unit, and wherein IRradiation from the two radiation units is uniformly distributed over thecross-sectional area and edges of the food support unit; and (iv) a driptray to store a lipid comprising liquid, wherein the drip tray is hostedwithin the radiation grill unit cavity in between the two radiationunits below the lower part edge of the lower part of the reflector ofeach respective radiation unit, and wherein the at least onesubstantially straight surface of the lower part of the reflector ofeach respective radiation unit is positioned at an angle relative tohorizontal, to block rays of IR radiation that would otherwise bedirected towards the drip tray and the reflector of the oppositeradiation unit of the two radiation units and thus render the drip trayand the reflector of the opposite radiation unit of the two radiationunits out of a line of sight of direct IR radiation from the IRradiation heater of a respective radiation unit.
 19. The radiation grillunit according to claim 18, wherein the drip tray further comprises adrip tray face and at least one drip tray reservoir, and wherein the atleast one drip tray reservoir is configured at a side edge of the driptray.
 20. The radiation grill unit according to claim 18, wherein thefood support unit comprises a grill grid with a one-dimensional array ofbars arranged in parallel, each bar having a bar length with two ends,an intermediate portion, and two sloping portions configured tofacilitate transport of lipids in a direction of a middle of the bar,and wherein each sloping portion is in between a respective end of thebar and the intermediate portion, the intermediate portion being locatedin the middle of the bar.